The present invention relates to surgical tools and procedures generally and relates more particularly to the use of ablation to treat atrial fibrillation and other disorders.
In patients with chronic atrial fibrillation having tachycardia that resistant to medical treatment, the Maze procedure has been employed. This procedure controls propagation of the depolarization wavefronts in the right and left atria by means of surgical incisions through the walls of the right and left atria. The incisions create blind or dead end conduction pathways, which prevent re-entrant atrial tachycardias from occurring. While the Maze procedure is successful in treating atrial fibrillation, the procedure is quite complex and is currently practiced by only a few very skilled cardiac surgeons in conjunction with other open-heart procedures. The procedure also is quite traumatic to the heart, as in essence the right and left atria are cut into pieces and sewn back together, to define lines of lesion across which the depolarization wavefronts will not propagate.
It has been suggested that procedures similar to the Maze procedure could be instead performed by means of electrosurgical ablation, for example, by applying RF energy to internal or external surfaces of the atria to create lesions across which the depolarization wavefronts will not propagate. Such procedures are disclosed in U.S. Pat. No. 5,895,417, issued to Pomeranz, et al., U.S. Pat. No. 5,575,766, issued to Swartz, et al., U.S. Pat. No. 6,032,077, issued to Pomeranz, U.S. Pat. No. 6,142,944, issued to Swanson, et al. and U.S. Pat. No. 5,871,523, issued to Fleischman, et al, all incorporated herein by reference in their entireties. Hemostat type electrosurgical or cryo-ablation devices for use in performing such procedures are described in U.S. Pat. No. 5,733,280 issued to Avitall, U.S. Pat. No. 6,237,605 issued to Vaska, et al, U.S. Pat. No. 6,161,543, issued to Cox, et al., PCT published Application No. WO99/59486, by Wang and in pending U.S. patent application Ser. No. 09/747,609 filed Dec. 22, 2000 by Hooven, et al., all incorporated herein by reference in their entireties. In order for such procedures to be effective it is desirable that the electrosurgically created lesions are continuous along their length and extend completely through the tissue of the heart. In order for such procedures to be effective it is desirable that the electrosurgically created lesions are continuous along their length and extend completely through the tissue of the heart. Analogous issues arise when attempting to create continuous lines of lesion through the walls of other heart chambers or other organs.
According to the present invention elongated lesions as might be desired in a maze type procedure or other procedure may be produced using a set of two elongated ablation components carrying means (e.g. an electrode or electrodes) for applying ablation energy (e.g. RF energy) along its length. The ablation components are adapted to be arranged on opposite sides of the walls of the atria or other hollow organs, on either side of the organ walls and to ablate or create lesions in the tissue between the components. The ablation components may also be arranged along opposing external surfaces of an organ, for example opposite sides of an atrial appendage or along opposite sides of the tissue adjacent the bases of the right or left pulmonary veins.
The ablation components are provided with a magnetic system for drawing the components toward one another to compress the wall or walls of an atrium or other hollow organ therebetween, along the length of the components. In these systems, at least one of the components is provided with a magnet or series of magnets extending along the component. The other component is provided with a ferromagnetic member or preferably another magnet or series of magnets extending along its length, having polarity chosen to assure attraction between the two components. The magnet or magnets may be rigid or flexible and may be formed of magnetic material, e.g. rare earth magnets, or may alternatively be electromagnets.
In one preferred embodiment of the invention, the two components comprise opposing jaws of an electrosurgical hemostat, provided with elongated RF electrodes and having straight or curved configurations. In some of these embodiments, the jaws of the hemostat are both rigid and the magnets are present primarily to assure good contact and alignment between the jaws, along their length. In other embodiments, one jaw may be rigid and the other flexible, for example to allow it to be temporarily deformed to access desired locations. In these embodiments, magnetic system also assists the flexible jaw in returning to a configuration corresponding to the rigid jaw, as the jaws are brought into proximity to one another. In some embodiments, one jaw may be shapeable, so that the physician can select a desired configuration, with the other jaw being flexible. In these embodiments, the magnetic system allows the flexible jaw to automatically assume a configuration corresponding to the shapeable jaw. In other embodiments, both jaws might be flexible.
Similar sets of embodiments may be provided wherein the two components are separate from one another, for example mounted to separate handles. Alternatively, a first, external component might be mounted to a handle, to he held by the physician, while a second, internal component may be located on a percutaneously introduced catheter. In these embodiments, the internal component would typically be quite flexible, while the external component would be either rigid or shapeable. In these embodiments the magnetic system allows the internal component to automatically assume a configuration corresponding to the external component, after introduction of the internal component to the interior of the hollow organ.